The proposed research is designed to develop more effective self-change models and materials for smoking cessation. Although smoking is the most preventable cause of cancer, 54 million Americans continue to smoke. Sixty percent of these smokers tried to quit but failed. Most smokers report that they would not attend formalized treatment programs but would use self-help materials. Unfortunately, available self-help manuals have been as ineffective as formalized treatment programs. Consequently, there is an urgent need to develop and disseminate more effective models and materials for individuals wishing to quit smoking on their own. The proposed research is a continuation of five years of research on self-change approaches to smoking cessation. These studies have enhanced a Transtheoretical Model which involves ten change processes receiving differential use during four stages of change: precontemplation; contemplation; action; and maintenance. Causal modeling would be continued on a two-year longitudinal data set of 950 smokers and former smokers. Structural analyses would test causal models of the processes which are most effective for the precontemplation, maintenance and relapse stages of change. Relapse analyses of self-changers would identify the antecedents and the positive and negative consequences of relapse. Currently funded Phase II research is developing self-help modules and computer-assisted correspondence courses for the contemplation and action stages. The proposed research would complete Phase II research through the development of modules and correspondence courses for the precontemplation, maintenance and relapse stages. Longitudinal Phase III research would then evaluate four different self-help programs: 1. the combined action and maintenance manuals of the American Lung Association; 2. a more individualized transtheoretical manual that includes modules for five stages of change; 3. a transtheoretical computer assisted correspondence course that provides individualized and interactive applications of the five modules; and 4. a computer and counselor assisted correspondence course that provides individualized, interactive and personalized applications of the five modules. A three year longitudinal analysis of 1600 subjects would provide intensive process and outcome evaluations of the four programs. This research is designed to contribute to cancer control by developing and evaluating more effective self-help models and programs that have potential for providing desirable and cost-effective help to large numbers of individuals wishing to stop smoking.